test cases for the unfinished firmware c2n232i.s: ensuring that NUL character works: ^J -> <- ':' ^@^@^@^@ <- nothing ^@ <- '0' disk load emulation: ^J^I^I^I^I -> <- ':' LOAD"FILE",8 <- (~p^@^BFI2^@^D?^@^B^@^AH`^@^C ^LZ -> <- '<' ^A^B^C^D^E^FABC^@^@^@^@^@^A^@^@ -> <- ^@ <- ~^@_^@^B^@^A(~`?^@^B ^@^J -> <- ':' LIST 1541 ABC sending command to disk (fails): ^LZ -> <- '<' ^@^B( (TALK, device 8) <- ^A^@ (device not present after sending 0 bytes) ^@^J -> <- ':' Measurement of the serial bus: ATN ŻŻŻ________________________________________ŻŻŻŻ CLK ŻŻŻŻ___________Ż_Ż_Ż_Ż_Ż_Ż_Ż_Ż_Ż___________ŻŻŻŻ 1ms 1ms DATA ŻŻŻŻ____________Ż_Ż_Ż_ŻŻŻ_ŻŻŻ_Ż_ŻŻŻŻŻŻŻŻŻŻŻ_ŻŻŻ 0 0 0 1 0 1 0 0 For some reason, the disk drive unit will not drive the DATA line low in response to the command.